Breast Stroma Neoplasms Quiz

Understanding Fibroadenomas: Key Points

• Fibroadenomas are associated with higher levels of plasma estradiol, suggesting estrogen dependency for their growth, and tamoxifen treatment reduces their proliferation activity.
• Cellular analyses show that both stromal and epithelial cells in fibroadenomas are polyclonal, indicating they are hyperplastic lesions rather than true neoplasms.
• Mutations of the MED12 gene have been identified in up to 65% of fibroadenoma cases, indicating monoclonality and suggesting some fibroadenomas may be neoplastic rather than hyperplastic lesions.
• Fibroadenomas usually present as solitary, painless nodules, but in 15% of cases, they can be multiple and may grow rapidly under certain conditions such as pregnancy, hormone replacement therapy, or immunosuppression.
• Grossly, fibroadenomas appear as spherical nodules with a whorled-like pattern, and microscopically, they show combined proliferation of mesenchymal and epithelial elements.
• Fibroadenomas are markers for increased risk of breast cancer, with a 1.3 to 2.1 increased risk compared to the general population, and there are simple and complex subtypes with varying risks.
• Malignant transformations within fibroadenomas are rare, with the incidence of carcinoma in situ or invasive breast carcinoma evolving within a fibroadenoma being reported as 0.002% to 0.0125%.
• On mammograms, fibroadenomas appear as smooth-margined oval or round masses, and on ultrasound, they appear solid, well-circumscribed, and hypoechoic.
• Most fibroadenomas grow to a size of 2 to 3 cm over a 12-month period, after which they remain unchanged for several years, and regression or complete resolution is noted in 50% of cases.
• Fibroadenomas are very uncommon in the male breast and are usually diagnosed clinically as gynecomastia, presenting with an enlarged breast and a painful nodule.
• Fibroadenomas have a spherical, sharply demarcated appearance with a firm, grayish-white consistency, and a whorled-like pattern upon cut section.
• The stromal component of fibroadenomas is made up of loose connective tissue, while the epithelial component arises from the terminal duct lobular unit, leading to two main histological features: intracanalicular and pericanalicular.